1. Field of the Invention
This invention relates to a drilling apparatus.
2. Discussion of the Prior Art
Currently available diamond drilling rigs are usually large, heavy assemblies, which are susceptible to movement during drilling. Such rigs, which are intended to deep well drilling (2000-3000 feet) include a derrick mounted on a platform fur supporting the remaining elements of the rig. During drilling on soft ground, the reaction between the drill string and the derrick tends to push the platform upwardly. When pulling the drill string upwardly, the platform tends to sink into the ground. In either case, the derrick and consequently the drill string can become misaligned with the borehole or well.
An object of the present invention is to provide a solution to the above-identified problem in the form of a relatively simple, portable drilling apparatus which can be anchored to the bedrock during drilling or core sample removal, and consequently cannot become misaligned due to reaction forces between the drill and the rock.
Another object of the invention is to provide a lightweight, modular drilling apparatus, which is easy to assemble and disassemble. A lightweight modular apparatus of the type described herein is air portable. The elements of the apparatus can be delivered in the order in which they are to be assembled by helicopter to a drilling site where the apparatus is quickly put together in a matter of hours. Upon completion of a drilling operation, the process is reversed, and the elements of the apparatus can be expeditiously removed from the drilling site. There is no need for a large heavy derrick, which cannot be assembled and disassembled in a short time.
Accordingly, the invention relates specifically to a drilling apparatus for use with a well casing anchored in the ground at the start of a drilling operation, and a platform for positioning at a drilling site, said apparatus comprising:
(a) a mast for mounting on said platform for rotation between a horizontal use position and an inclined or vertical drilling position;
(b) a rod clamp fixedly mounted on one end of said mast for clamping a drill rod during a drilling operation;
(c) a casing clamp on said one end of said mast for clamping said mast to a top end of said casing, whereby the mast is anchored to the ground during drilling operation;
(d) a drill head slidably mounted on said mast for movement toward and away from said rod clamp, said drill head being adapted to drive a drill rod during a drilling operation; and
(e) a main ram connected to said mast and said drill head for moving said drill head longitudinally of the mast during a drilling operation.